A new smile for Andrea – digitally manufactured interim rehabilitation
Eric Kukucka shows digitally manufactured interim rehabilitation of a challenging case.
The following article describes the interdisciplinary treatment approach taken to treat a young patient who suffered considerably from physical and psychological issues which stemmed from her dental condition (Figure 1).
In order to solve such a case, the smooth collaboration of the dental practice and the dental laboratory is indispensable, in addition to excellent dental and dental laboratory expertise and coordinated manufacturing techniques. In the present case, the solution started with an interim denture, which allowed the patient to regain her ‘normal’ jaw function and aesthetic appearance.
When Andrea consulted us for the first time at 25 years of age she had already suffered from various symptoms for several years. Her complaints were caused by two different disorders, which led to serious consequences, individually and in combination. The young woman suffered from a genetic disorder, one of the symptoms of which presents as very weak tooth enamel. Furthermore, the patient was afflicted with fibromyalgia, a chronic pain disorder accompanied by immense psychological stress. As a consequence, the patient had been vomiting three to four times a day on average over a period of several years. The resultant acid erosion significantly damaged her already severely compromised dentition (Figure 2).
Effects of the illness
The patient reported that she was experiencing unbearable pain and that she had suffered numerous oral infections. Over the years, Andrea had to take ‘countless’ courses of antibiotics, the effectiveness of which diminished over time. As a result of these infections, several teeth had to be extracted. Andrea’s grave oral health situation interfered with her ability to eat.
The unattractive appearance of her teeth profoundly affected her emotionally. Her mental health and her self-concept suffered as a result. She described her previous dentist visits as ‘horrendous’ experiences. Therefore, she was initially reluctant to agree to the suggested complex treatment. However, we were able to convince her of the necessity of the procedure in the course of very caring and empathetic conversations.
After many discussions, an initial treatment goal was defined: The teeth that could not be saved would be extracted and an interim denture would be fabricated as a temporary solution. In a treatment second phase, implants would be placed. As a first priority, however, we focused on improving the patient’s quality of life.
We chose to use the Digital Denture process in order to offer the patient a “comfortable” treatment modality and ensure predictable results for the dental team. Since the patient did not wish to be toothless at any stage of the treatment, an interim denture had to be available at the tooth extraction appointment.
First of all, impressions of the upper and lower jaws were taken and the models were cast. Subsequently, the models were digitised with a laboratory scanner (3Shape). The data records were transferred to the Digital Denture software program, which allowed us to fabricate a set of tooth-coloured dentures with SR Ivobase CAD and SR Vivodent CAD Multi using an automatic manufacturing process.
CAD construction of the interim denture
Before the interim denture could be designed, the remaining teeth had to be removed from the virtual model (Figure 3). For this purpose, the software program features a virtual extraction tool. The software guided us through the model analysis process, one step at a time. We marked the anatomical characteristics and established the significant parameters for the denture (Figure 4).
Based on the maxillomandibular relationship record, the vertical dimension was opened by 5.5 mm (Figure 5a). Suitable tooth moulds were selected from the Digital Denture Full Arch tooth library (Phonares II B71-L50-N3) (Figure 5b).
The software automatically generated a suggestion for setting up the selected teeth (Figure 6). If desired, this set-up can be customised. Next, we checked the basic parameters (tooth length, midline, bite and so on) and made the necessary fine adjustments in the software.
In addition, we finalised the denture base and characterised the gingival contours. The software offers various tools for adding, removing or smoothing dental material.
CAM manufacturing of the interim denture
The CAD file was saved and the software generated a CAM output file for milling the dental arch and the denture base. The dental arch was milled from a biocompatible, highly cross-linked polychromatic PMMA-based DCL material (SR Vivodent CAD Multi) (Figure 7). It is characterised by its special Pearl Structure Effect, which ensures an even progression of the shade. We selected shade A1. The multi-chromatic colour gradient of the disc – incisal, dentine, cervical area – imparts the milled monolithic teeth with a very natural looking appearance with very little reworking. The Digital Denture system incorporates a number of different gingiva coloured PMMA discs (Ivobase CAD). The shades of these discs are matched to those of the Ivobase denture base materials (preference Pink, Pink V, 34V) (Figure 8).
The oversize process
In a first step, the CAM machine (Programill PM7) coarsely milled the dental arch. The dental arch was produced in oversized form and the base surfaces were exactly milled to fit the denture base (Figure 9). In the next step, the tooth arch and the denture base were bonded together.
An efficient, easy-to-use, self-curing two-component bonding agent was used (Ivobase CAD Bond) for this purpose (Figure 9). The tooth arch and the denture base were finalised in the subsequent precision milling and finishing process (Figures 10 and 11).
Completion of the interim dentures
The digitally manufactured dentures required only minimal finishing. The morphology of the vestibular areas – a blend of concave and convex areas – of the denture base had been saved to the software and then machined in a 1:1 ratio. At this stage, the micro texture of the teeth and the gingiva can be customised. Fine wear facets can be added if desired in order to enhance the lifelike appearance of the denture. In the present case, the denture was pre-polished with a dental handpiece and then polished to a final high gloss in a polishing unit, using pumice and a universal polishing paste and a cotton buffing wheel.
Tooth extraction and the new smile
The teeth were extracted under full anaesthetic and slight alveoloplasty was conducted. As a result, ideal conditions were created for the denture. The patient left the practice after the surgical intervention wearing the new interim denture. One week later she presented to the practice for a recall appointment. By that time not only her appearance, but also her demeanour had changed remarkably. She radiated vitality and self-confidence (Figure 12).
The primary treatment phase represented an important part of the overall rehabilitation. The patient obtained a beautiful smile and a measurably improved quality of life (Figure 13). Due to the Digital Denture system, the treatment required relatively little time and effort. Today, the young woman is broadly happy, self-assured and motivated to take the next treatment step.
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